Per gunnar backmast



(No Model.)

P. G. BAGKMAN.

k LIFT, HOIST, Gas. No. 515,641.

Patented Feb. 27, 1894 m! NATIBNAL umoemwumu wnnmnmu. a. c.

UNITED STATES PATENT EEicE.

PER GUNNAR- BACKMAN, OF PARIS, FRANCE.

LIFT, HOlST, aw.

SPECIFICATION forming part of Letters Patent No. 515,641, dated February27, 1894.

Application filed August 4, 1891. Serial No. 401,719. (No model.)Patented in Sweden January 12, 1891, No. 3,546, and inBngland July 16,1391, No. 12,120.

1'0 a/ZZ whom it may concern.-

Be it known that 1, PER GUNNAR BACK- MAN, a subject of the King ofSweden and Norway, residing in Paris, (Seine) Republic of France, haveinvented certain Improvements in and Relating to Lifts, Hoists, or otherElevating Apparatus, (for which I have obtained a Swedish patent, No.3,546, dated January 12, 1891, and a British patent, No. 12,120, datedJuly 16, 1891,) of which the following is a specification.

My invention relates to lifts, hoists and other elevating apparatus.

It consists in a special arrangement of a hydraulic motor designed toset lifts in action and reduce the expenses of installation and also thespace occupied by the motor for the lifts or hoists as hereinafterdescribed and claimed.

In order to make my invention clearly understood I will proceed todescribe the same in detail with reference to the accompanying drawings,in which- Figures 1 and 2, represent in diagram the whole arrangement ofa lifting apparatus or hoist constructed according to my invention. Fig.8, is a side elevation of the motor and connections. Fig. 4, is aview atright angles to the plane of Fig. 3, partly in section.

In all the before mentioned figures corresponding parts are designatedby similar letters.

The two cables, B, B, are fastened in a special manner to the cage, A,and after passing over the two upper guide pulleys, B, B, are fixed tothe two lower drums, D', D. These cables may be attached to any approvedform of safety devices carried by the elevator car, so that the breakingof either cable will throw the safety device into action. According tothe direction of rotation of these drums the traction cables aresimultaneously wound and unwound so as to cause the ascent or descent ofthe cage or platform, A. These drums although situated side by side areindependent of each other and on their respective shafts are keyedpinions, d d, with which engage the chains, 0 c, which are free at oneend and at tached by the other to a counter weight, E, fixed to a pistone, of a hydraulic press or cylinder, F. By this independent arrangementof the drums and connections the load is equally distributed between thetwo cables. The details of the drums, D D, of the pinions dd, thecounter weight, E, with plunger 6, and the hydraulic cylinder, F, areshown in Figs. 3 and i.

While I have shown the counterweight attached to the piston it isobvious that the same result will be effected by making the cylindermovable while the plunger is fixed to the bed, and attaching the saidcounterweight to the cylinder, or the counterweight may be separate fromthe plunger and connected thereto in any suitable manner by a chain. Itis also obvious that the cylinder may be divided into two compartmentswith aplunger in each attached to the drums D D respectively. Whateverthe arrangement adopted or employed, the drums, D'D, have a diameter ntimes greater than that of the pinions, d d, so that the total movementof the piston e, is n times less than that of the cage, A, of the lift.From this it results that the counterweight, E, should weigh n timesmore than the weightb'f the cage including its maximum load. When thewater or other fluid under pressure is admitted into the cylinder, F,through the pipe f the plunger piston e rises and the cage or platform,A, exercising the same traction on the suspension cables, B B, pulls thedrums, D D, which begin to move in the direction of the arrows (Fig. 1),that is to say in opposite directions and through the medium of thepinions, d d, stretch the chains, 0 c. When on the contrary the waterisdischarged, the counterweight and plunger, E 9, cause the cage orplatform to rise in a contrary direction. Ac-

cordingly the traction cables, B B, during the descent of the cage orplatform, A, directly affect the rotation of the drums, D, D, held bythe chains, 0 0, whereas during the upward movement the weight of thecage A acting through the traction cables, causes the movement of thedrums. The admission and discharge of the water are effected through themedium of a valve easily actuated from any point by a cord extending theentire height of the cage and one portion of which runs

